Photoelectrochemical reactions in aqueous systems represent a promising route for solar fuel production; however, their efficiency is often constrained by the sluggish kinetics of the anodic oxygen evolution reaction (OER). BiVO4 is one of the most promising photoanode materials and has demonstrated the ability to efficiently convert light into electrical and then chemical energy. However, the conversion efficiency of pure BiVO4 remains insufficient. In this work, BiVO4 photoanodes are first modified with FePO4 using a simple Autodrop process and subsequently integrated with Ti3C2T x MXene overlayers deposited via automated spray coating. The thus modified photoanodes exhibit a superior performance thanks to the synergistic interaction between the FePO4 and MXene layers, which promotes the movement of electrons and efficient charge separation, thus suppressing surface recombination in BiVO4. Meanwhile, both the FePO4 and MXene layers can act as hole-transport channels and co-catalytic interfaces, facilitating interfacial charge transfer and accelerating OER kinetics. Importantly, achieving an optimal balance between MXene coverage and FePO4 exposure is critical to maximizing catalytic activity within the BiVO4/FePO4/MXene heterostructure. By optimizing the MXene loading, the modified BiVO4/FePO4 photoelectrode exhibits an approximately 50% improvement in photocurrent performance. Overall, this work presents a simple and effective strategy for fabricating high-performance photoanodes with potential for scalable production. The proposed heterojunction design provides a promising pathway toward the development of efficient and stable photoanodes for solar fuel applications.
The escalating discharge of industrial waste has hampered access to clean and potable water.
Multi-material adhesively bonded joints between carbon fiber reinforced polymers (CFRPs) and metals are used in many high-end applications in automotive and aerospace industries, with adhesives having multiple benefits over mechanical...
The development of efficient bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is critical for advancing renewable energy technologies. In this work, we design and synthesize a hierarchical exfoliated exfMoS2@Ti3C2T x @α-Ni(OH)2 heterostructure that functions as a highly active bifunctional electrocatalyst under acidic conditions. The catalyst exhibits excellent catalytic activity for electrochemical water splitting, delivering low overpotentials of 127 mV for the HER and 280 mV for the OER at a current density of 10 mA cm-2 in 0.5 M H2SO4. Furthermore, a symmetric H-cell device using exfMoS2@Ti3C2T x @α-Ni(OH)2∥exfMoS2@Ti3C2T x @α-Ni(OH)2 electrodes achieves an overall water splitting voltage of 1.61 V to reach 10 mA cm-2 with robust stability over 72 h of continuous performance. Density functional theory (DFT) calculations, combined with Gibbs free energy analyses, reveal the electronic band structures of the exfMoS2@Ti3C2T x @α-Ni(OH)2 heterostructure and corroborate its enhanced catalytic activity. The synergistic integration of exfMoS2, Ti3C2T x , and α-Ni(OH)2 promotes efficient charge transfer, optimizes hydrogen and oxygen intermediate adsorption, and accelerates reaction kinetics. This study demonstrates the potential of exfMoS2@Ti3C2T x @α-Ni(OH)2 as an efficient bifunctional electrocatalyst for the HER, the OER, and overall water splitting and provides mechanistic insights into the electrochemical processes involved.
In the present investigation, a highly porous pure α-Al2O3 foam (92% porosity) was fabricated using the thermo-foaming method. Later, zinc oxide (ZnO) nanorods were grown on the α-Al2O3 foam by...
Despite major advances in sanitation, vaccination, and antimicrobial chemotherapy, infectious diseases continue to pose a huge threat to global health. The ever-increasing occurrences of antimicrobial resistance, emerging pathogens, and persistent diagnostic delays further exacerbate this situation. Over the years, nanotechnology has generated a lot of material platforms to address these failures, and in this study, we critically examine nanoclusters-ultrasmall, atomically precise assemblies (<2 nm cores) with discrete electronic states, as an under-recognized but potentially transformative class of materials for infectious disease diagnostics and therapeutics. Their quantized optical properties, precision ligand chemistry, and unusually high surface-to-volume ratios enable behaviours fundamentally inaccessible to larger nanomaterials, including ratiometric fluorescence reporting, rapid redox-driven antimicrobial activity, and programmable bio-recognition at near-molecular resolution. First, we disentangle NCs from larger nanomaterials by focusing on the consequences of discrete electronic states, ultrasmall hydrodynamic radii, and well-defined ligand shells for transport, clearance, and interactions with pathogens and host-derived biomolecules. Furthermore, the review synthesizes advances in NC-enabled diagnostics, including DNA and aptamer templated Au, Ag, and Cu NC probes, CRISPR/Cas integrated ratiometric sensors, and nanozyme-based readouts that routinely achieve single colony-forming unit or sub-femtomolar detection of bacterial, viral, fungal, and protozoan nucleic acids and antigens. On the therapeutic side, we discuss how the same structural characteristics can be exploited to engineer NCs that mediate controlled ROS generation, membrane and biofilm disruption, quorum sensing interference, photothermal and NIR II photodynamic therapy, and ligand-directed drug delivery, with case studies spanning multidrug-resistant bacteria, opportunistic fungi, and selected parasitic infections. At the same time, we looked at some of the major barriers to clinical translation that remain unaddressed. We show with this study that nanoclusters are not merely "smaller nanoparticles" but a distinct chemical system, capable of enabling modular, multiplexed, and clinically relevant infectious disease interventions. To realize this potential, future work must couple atomic-level design with rigorous pharmacokinetic, toxicodynamic, and translational engineering frameworks.
Plasmonic refractive-index sensors provide a powerful route for label-free detection, but their performance is often limited by the trade-off between sensitivity and resonance linewidth. Here, we propose a magneto-optical hyperbolic metamaterial platform for high-resolution refractive-index sensing at the telecom wavelength of 1550 nm. The structure consists of an Au diffraction grating, a cerium-substituted yttrium iron garnet (CeYIG) magneto-optical layer, and an Ag/SiO2 multilayer hyperbolic metamaterial. Finite-element simulations show that the grating enables efficient coupling of incident p-polarized light to bulk plasmon polariton modes supported by the hyperbolic stack. By optimizing the CeYIG layer thickness, a critical-coupling condition is achieved for the fundamental BPP0 mode, resulting in a strongly enhanced transverse magneto-optical Kerr effect (TMOKE) response. The angular position of the TMOKE resonance exhibits a linear dependence on the refractive index of the surrounding aqueous medium, yielding an angular sensitivity of 78° RIU-1. Owing to the narrow Fano-like TMOKE resonance, the figure of merit varies from 5720 to 9750 RIU-1, averaging 7990 RIU-1 over the investigated refractive-index range, with the maximum occurring at n an = 1.335. These results indicate that grating-coupled magneto-optical hyperbolic metamaterials offer a promising strategy for compact, label-free, and high-resolution refractive-index sensing.
Due to its superior physical and chemical characteristics, MXene quantum dots (MXQDs) are regarded as an outstanding zero-dimensional nanomaterial. The excitation of these QDs dependent on emission properties, photostability, biocompatibility...
A comprehensive study is reported on two types of 3D graphene foam (GF) exhibiting distinct defect density, structural and functional properties. Wettability characterization demonstrates that high defect GF and low defect GF are hydrophilic, with a contact angle (CA) of approximately 14° and 72°, respectively. Optical characterization demonstrates close to zero reflectance and transmittance over a spectral range of 350 nm to 25 µm. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDS) provide insight into chemical composition, defect density, and functionalization, while atomic force microscopy (AFM) shows that the high defect GF (HDGF) has a pronounced surface roughness, with a maximum surface roughness of over 18 nm. However the low defect GF (LDGF) exhibits a significantly smoother and more uniform surface with a maximum surface height of 4.5 nm. Electrochemical characterization demonstrates the impact of network connectivity on charge transport, highlighting differences in resistance and percolation thresholds between the two HDGF and LDGF foam types with areal capacitances of 38 and 32 µF cm-2, respectively, at a current density of 0.1 mA cm-2. The values show 90% and 94% retention of the initial capacitance when current density was increased 50-fold. A detailed structure-property-function relationship is established for the GF materials, useful for various applications.
Access to sub-micrometer electrode patterning remains limited in laboratories without lithographic or specialized mask-fabrication facilities. We present a novel, low-cost method for fabricating microdevices using nail-polish microfibers as shadow masks. A thin fiber is drawn by repeatedly touching a nail-polish droplet with a wire loop and placed directly onto the target substrate to define narrow features for metal deposition. As-drawn fibers reach diameters down to ∼2 µm and conform to both rigid and flexible surfaces. Oxygen-plasma thinning at ∼22 nm min-1 reduces fibers initially ≥4 µm in diameter to below 1 µm, enabling electrode gaps down to ∼478 nm, as confirmed by atomic force microscopy. The process requires no spin-coated photoresist, baking, or development. Using this approach, we pattern microelectrodes on SiO2/Si and polycarbonate and realize functional devices, including MoS2 field-effect transistors, MoS2 photodetectors, and a flexible device based on chemical vapor deposition-grown MoS2. The method requires no photolithography, minimizes material cost, and leverages readily available tools and consumables, providing a practical route to prototyping and education as well as laboratory microfabrication.
The scalable production of graphene with controlled chemical functionalities remains a central challenge in translating laboratory advances into practical technologies. Beyond conventional approaches that prioritize the surface area, functionalization or conductivity, increasing attention is being directed toward spatially selective defect engineering that preserves the aromatic π-conjugated carbon framework while enabling targeted interfacial reactivity, thereby providing high-quality graphene. In this context, shear-driven ball milling has emerged as a promising mechanochemical route for the synthesis of edge-functionalized graphene through preferential edge activation and controlled exfoliation. Unlike oxidation-intensive methods that often introduce extensive basal-plane damage, shear-assisted milling promotes layer delamination while largely preserving the intrinsic sp2 carbon network. Simultaneously, the mechanochemical environment activates newly generated edge sites, enabling direct reactions with selected milling agents and facilitating controlled incorporation of heteroatoms and functional groups. Such edge-focused functionalization provides an effective means of balancing electrical conductivity, wettability, ion accessibility, and electrochemical activity. This review critically examines the mechanistic principles governing graphite exfoliation during ball milling, the roles of milling agents and processing parameters in regulating structural evolution and surface chemistry, and the characterization strategies used to distinguish edge functionalization from basal-plane modification. Particular emphasis is placed on understanding the relationships between processing conditions, defect generation, functionalization pathways, and electrochemical performance. The influence of edge-engineered graphene on charge storage mechanisms in supercapacitors, lithium-ion batteries, sodium-ion batteries, zinc-ion systems, and hybrid energy-storage devices is comprehensively discussed. In addition, key considerations related to scalability, process economics, sustainability, contamination control, energy consumption, reproducibility, and industrial implementation are evaluated. Overall, this review establishes a process-structure-electrochemistry framework for shear-driven ball-milled graphene and highlights its potential as a scalable platform for the development of advanced graphene materials tailored for next-generation energy-storage technologies.
This study introduces the development of an innovative and environmentally friendly bio-nanocatalyst (CoFe2O4@CS-BAPT/CuII nanocomposite), designed and employed for three-component synthesis of 2-amino-3-cyano-4H-pyrans. Chitosan (CS) as a biodegradable polymer was functionalized with bis(2-aminopyridine)triazine (BAPT) moieties. Subsequently, CoFe2O4 magnetic nanoparticles (MNPs) were incorporated and copper ions were immobilized on the composite to form the final magnetic nanocomposite (CoFe2O4@CS-BAPT/CuII). Characterization techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) analysis, vibrating sample magnetometry (VSM), inductively coupled plasma atomic emission spectroscopy (ICP-OES), dynamic light scattering (DLS), and zeta potential were used to analyze the nanocomposite structure. XRD analysis showed a near-amorphous structure after functionalizing CoFe2O4 with chitosan. FE-SEM images revealed uniform particles without aggregation, with an average size of 12-14 nm. TGA indicated thermal stability up to 300 °C. CoFe2O4@CS-BAPT/CuII was successfully used in the green synthesis of 2-amino-3-cyano-4H-pyrans with potential biological properties. The desired products were synthesized with high yields (83-95%) in short reaction times (20-45 minutes). Furthermore, the catalyst exhibited easy magnetic separation and good reusability, highlighting its potential as an efficient and sustainable heterogeneous catalyst. Key advantages of this approach include the use of an easily accessible bio-polymer, environmentally friendly catalytic protocols, a simplified and cost-effective synthesis process, clean reactions that generate no additional waste, and the reusable nature of the catalyst.
The influence of porosity and surface functionalization strategies on the biosensing performance of nanoporous anodic alumina rugate filters (NAA-RF) is systematically investigated using reflectometric interference spectroscopy (RIfS). Highly ordered NAA-RF...
Atomic layer deposition (ALD) of ZnO enables conformal nanoscale coating on cotton textiles, imparting multifunctional properties for high-performance and smart fabric applications. However, the influence of ALD processing temperature on...
The occurrence of Ibuprofen in surface and wastewater is an emerging environmental concern due to its incomplete removal in conventional water treatment systems. In this work, ZnO-based hybrid photocatalysts decorated...
Hydrostatic-pressure, external electric-field, and aluminium-composition-controlled magneto-optical response in the GaAs/Al λ Ga1-λ As nanostructure with asymmetrical Gaussian confinement, is investigated applying the projection-operator framework. The magneto-optical response is systematically probed via the optically detected magneto-phonon resonance (ODMPR) effect, including strength, shift, and full width at half maximum (FWHM) of the ODMPR peak induced by intersubband and intrasubband transitions for absorption and emission processes of LO-phonons. The results show that: (i) the magneto-optical response probed via the ODMPR effect can be effectively controlled through both external and structural parameters; (ii) the magneto-optical response induced by both the intrasubband and intersubband transitions is very sensitive to the hydrostatic pressure and aluminium composition, while only the intersubband transition is sensitive to the external electric field; (iii) among the intersubband transitions due to phonon absorption and emission, and intrasubband transitions due to phonon emission, the FWHM of GaAs/Al λ Ga1-λ As asymmetrical Gaussian potential heterostructures resulting from intersubband transitions with phonon absorption are the largest and the most sensitive to variations in hydrostatic-pressure, quantum system temperature, and aluminium-composition λ, followed by the intrasubband transition due to phonon emission, while the intersubband transition due to phonon emission is the smallest and the least sensitive; (iv) and the sensitivity of the magneto-optical response to external electric field, confinement potential depth and width of the GaAs/Al λ Ga1-λ As nanostructure under the influence of aluminium composition and hydrostatic pressure, is also shown in detail. Comprehensive characteristics of the magneto-optical response of the GaAs/Al λ Ga1-λ As nanostructure are provided in the Conclusions, which are useful for the application potential of optoelectronic devices.
Cesium lead halide perovskites are promising materials for light-emitting diodes (LEDs) due to their tunable band gaps, defect tolerance, and high photoluminescence quantum yields (PLQYs) with narrow emission widths. In particular, mixed-halide CsPb(Br/Cl)3 nanocrystals (NCs) are promising candidates for true-blue light emission. The properties of these materials are influenced by both their size and composition; however, research on the synthesis conditions related to these two factors is limited. In this work, we systematically investigate the influence of reaction temperature on the morphology and optical properties of CsPb(Br/Cl)3 NCs synthesized via a hot-injection method. Morphological transformations from nanoplatelets to monodisperse cubic NCs were observed with an increase in reaction temperature. Optical spectroscopy shows a progressive red shift in emission, accompanied by a reduction in the peak linewidth and the Stokes shift. Bandgap energies determined from Tauc analysis strongly correlate with the size of cubic-shaped particles, as described by the Brus quantum confinement model. These results demonstrate that reaction temperature provides an effective strategy for controlling dimensionality, morphology, and excitonic properties of CsPb(Br/Cl)3 NCs, offering a simple pathway to tailor blue-emitting perovskite nanomaterials for optoelectronic applications.
This study reports a facile, one-step, and additive-free ion-exchange synthesis for the controlled formation of zinc oxide (ZnO) and zinc hydroxide (ε-Zn(OH)2) nanoparticles under room-temperature conditions with remarkably fast phase formation (within 2 minutes). The primary novelty lies in utilizing ordinary tap water as a green solvent, and an active chemical parameter to dictate phase evolution, thereby eliminating distilled water usage and energy-intensive thermal calcination. Structural and morphological characterization via XRD and TEM revealed a precise temperature-driven (15-45 °C) phase selection, yielding elongated ε-Zn(OH)2 structures at 15 °C, pure ZnO nanorods at 24-32 °C, and pseudo-spherical ZnO (9 nm) with a specific surface area of 35.76 m2 g-1 at 45 °C. Application of these nanomaterials in photocatalysis demonstrated exceptional efficiency, achieving over 99.2% methylene blue degradation under natural sunlight and 77% under indoor UV-A light (6 W lamp) within 150 minutes. Tauc plot analysis revealed a defect-induced bandgap narrowing, (E g ≈ 3.21-3.27 eV vs. 3.27 eV for bulk ZnO), expanding its light-harvesting capacity into the solar spectrum. Crucially, kinetic and thermodynamic analyses correlated this performance with an anomalous negative apparent activation energy (E ap), revealing a non-Arrhenius regime governed by exothermic adsorption-desorption equilibria, typical of a Langmuir-Hinshelwood mechanism. Furthermore, post-reaction FTIR analysis confirmed the high structural stability and photocorrosion resistance of the catalysts. Overall, these findings highlight a highly sustainable, energy-efficient, and industrially scalable pathway for fabricating high-efficiency photocatalysts for environmental remediation.
Two-dimensional laminar membranes with precisely controlled nanochannels have attracted significant attention for overcoming the permeability selectivity trade-off in water purification. Among them, MXene-based membranes exhibit unique advantages arising from their hydrophilic surfaces, rich surface terminations, and tunable interlayer spacing. This review presents MXene synthesis routes, including direct and in situ etching, hydrothermal processing, and emerging green approaches, with emphasis on their influence on flake morphology, surface chemistry, and stacking behavior. Membrane fabrication strategies, such as vacuum-assisted filtration, mixed-matrix integration, and interlayer engineering, are analyzed to establish correlations between structural features and separation performance. Particular attention is given to transport mechanisms within MXene nanochannels, where size sieving, electrostatic interactions, and confined transport collectively govern ion and molecule selectivity. Recent advances in crosslinking and nanoparticle intercalation are highlighted for effectively suppressing swelling and stabilizing angstrom-scale channels under aqueous conditions. MXene membranes demonstrate high rejection efficiencies with enhanced water permeance and antifouling properties across desalination, heavy metal removal, and organic contaminant separation. The remaining challenges, including scalable fabrication, structural stability, and defect control, are discussed to guide future development toward practical membrane applications.
In recent years, covalent organic frameworks (COFs) have emerged as powerful heterogeneous catalysts. Notwithstanding, attainment of both crystallinity and stability of COF-based catalysts under harsh conditions is still challenging. Herein, an imine-linked COF has been transformed into an amine-linked COF via the reduction of imine linkages. Amine linkages, due to their stable and irreversible nature, were functionalized with sulfonic acid groups, A-COF/SO3H, as a highly active catalytic center. X-ray diffraction (XRD) analysis clearly shows that the crystallinity of COF after modification was preserved. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses revealed that A-COF/SO3H has a plate-like intergrown morphology. The porosity of A-COF/SO3H was investigated by N2 adsorption/desorption, indicating a mesoporous structure with a surface area of 93 m2 g-1. To explore the catalytic performance, A-COF/SO3H was used as an acidic heterogeneous catalyst for the preparation of pyrrole-2-ones. Excellent yield of products, short reaction times and easy work-up are some of the major preferences of this protocol. Moreover, A-COF/SO3H exhibited good heterogeneity engineering potential and was recovered and reused up to four consecutive cycles without significant loss of its performance.
